The problem is also: How the hell do you want to slow down to properly touch down at low enough speeds?
You can use retro and hover thrusters at once yes, but that is a terrible way to slow down and extremely fuel consuming since you already need to counter gravity very soon for buying enough time to slow down on the usually weaker retros.
The best way is to use hover thrusters completely - but then you land finally vertically by definition of the best possible trajectory. Moon has no atmosphere, so you can't even try a VECTOR landing, like modern fighter jets with TVC can.
On Mars you could - there is still enough atmosphere left to slow down by it while using hover only to assist before landing. Still a pretty fast landing then.